Like all the shrines that you encounter in Zelda: Tears of the Kingdom, the Isisim Shrine also has its fair share of challenges. These will come in the form of a harsh environment and a lot of constructs here which will hinder your path and increase the difficulty, so make sure to take them out.
Moreover, in order to unlock the Isisim Shrine you need to progress in the main story and complete a certain quest. This quest will be known as Yunobo of Goron City quest and during this quest, you will need to break the walls near the entrance.
Once you solve the puzzle In Reverse here in the Isisim Shrine, then this particular shrine will be marked on your map as fast travel point as well. Moreover, you will also earn some rewards through the chests you explore at the Isisim shrine in Zelda: Totk.
That being said, if you are interested in the Isisim Shrine, then we have covered all the details regarding its location in this Legend of Zelda: Tears of the Kingdom guide.
Where to find the Isisim Shrine in Zelda: TotK

As for the location of the Isisim Shrine, you will come across it while following the Darunia Lake and heading east in Zelda: Totk.
Similarly, this shrine is also accessible if you head south from Lake Darman as well. However the Isisim shrine resides inside the YunoboCo HQ east cave in the Elden Canyon, so the exact coordinates for this shrine are (1838, 2387, 0363).
How to complete the Isisim Shrine in Zelda: TotK
So before entering the YunoboCo Hq east cave, it is vital that you equip yourself with the Flamebreaker Armor and the Desert Voe Headband in order to counter the hot flaming environment in Zelda: Totk.
After that you can simply proceed into the cave, break the walls, and enter the Isisim Shrine in Legend of Zelda: Tears of the Kingdom. Once inside you will not have your armor anymore as part of the test for the Isisim shrine.
There are a total of five constructs that you will have to fight and defeat in the Isisim Shrine. Once you find and defeat all five of these you will complete the puzzle In Reverse for the Isisim Shrine in Zelda: Totk.
So head downstairs and turn left. There you will encounter the first construct so defeat it using the bombs at its feet.
After defeating the first one head back to the large gear and use Link’s Rewind ability on it to reach the upper level.

There you will meet the second construct on your right. So kill him and proceed further down to meet the third one
The third construct will appear from the right side so you can deal with him with any weapon of your choice (e.g. Rusty Halberd, sword, etc.) You can also fuse the wooden stick with the Spiked Iron Ball to create a weapon to take out these constructs as well.
After you cleared the third construct the last two can be found at the opposite ends of the locked shrine gate.

You can stun it using arrow shots and then proceed to finish it off with sword attacks at close range. After you deal with the fourth construct on the left side you can proceed to fight against the last one on the right.
Like the rest follow the same attack pattern and you will be able to make quick work of this last construct in the Legend of Zelda: Tears of the Kingdom.
After you kill it you will get the following message stating that your equipment will be returned, and the challenge has been completed in the Isisim Shrine.
Then the gate in the middle will be unlocked for you and you can enter Totk. There you will find a green altar that you can interact with and this will mark the Isisim Shrine as complete in the Legend of Zelda: Tears of the Kingdom.